This invention relates to improvements in the lubrication of internal surfaces for internal gear pumps. More particularly, this invention relates to an improvement in the design of a gear pump's internal rotor such that the lubrication between the interface of the idler gear and the idler pin is greatly improved.
In a rotary internal gear pump, the idler gear rotates on a stationary pin. The idler gear is contained within the inner diameter of the rotor, the rotor's backwall and the face of the cover. The vast majority of the applications can have the idler gear rotate on the stationary idler pin without problem as the fluid being pumped provides sufficient lubrication. However, as the lubricating properties of the fluid are reduced and/or the operating pressures are increased, there has become a need for additional design features to aid in getting the fluid to the interface of the idler gear inner diameter and the idler pin outer diameter.
Previous designs have accomplished this by drilling one or more holes through the root of the idler gear, or by adding a groove on the face of the cover from the pressure side of the pump.
A need has arisen for an improved design for an internal gear pump. The present invention discloses an improved design for a rotor for an internal gear pump that greatly enhances the flow of fluid between the interface of the idler gear and the idler pin to provide lubrication.